The present invention relates to reciprocatory fluid pumps, and particularly to electromagnetic reciprocatory pumps widely used for low-pressure applications.
A large number of reciprocatory fluid pumps have been developed for low-pressure applications. They generally include a housing; an electromagnet fixed within the housing and defining an air gap; an armature assembly, sometimes called a plunger assembly or actuator, extending through the air gap and magnetically coupled to the electromagnet so as to be reciprocated thereby during the energization of the electromagnet; a pumping member, such as a diaphragm or a piston, mechanically coupled to the armature assembly so as to be reciprocated thereby; and a valve assembly cooperable with the pumping member, the valve assembly having an inlet port through which fluid is inletted and an outlet port through which fluid is outletted upon the reciprocation of the pumping member.
The known reciprocatory fluid pumps of this type generally include two pumping members, e.g., diaphragms, at its opposite ends, driven by two electromagnets. Other designs have been proposed including a single electromagnet driving two pumping members, e.g. diaphragms. Examples of such prior art pumps are described in U.S. Pat. Nos. 4,859,152 and 4,154,559.
The known reciprocatory fluid pumps of this type, however, are generally bulky, heavy and relatively expensive. In addition, the known reciprocatory fluid pumps generate considerable sound and vibration, as compared to rotary fluid pumps.